What does ethical feedism mean?
Make sure a feedee is into degrading before you start. Check in with their preferred language before you call them "cow" or "pig". Check in with their preferred gendered terms. (Some men might not like their chest referred to as breasts/tits) Even if they like being teased or bullied, comments like "disgusting slob" or healthplay might be too far. Respect the person first by respecting the boundaries.
Body shaming is the tool of the enemy. All body shaming, not just fat shaming. While I don't think "skinny shaming" is real, I still think you're an asshole if you put down skinny people. You don't know why they're skinny. Even if someone is being fatphobic, there are better ways to counter their argument than attacking their appearance. This applies to attacking someone's appearance based on them being bald, or having a neckbeard, or using micropenis as an insult.
If you're a thin feeder, be careful not to put yourself in a position of power above the feedee (outside of a scene). There is no moral value any body type has over any other. If you feel a sense of pride in being better than someone who has "let themselves go" (even if you don't vocalize this) that points to fatphobia and benefiting from thin privilege.
Stand up for fat people you're not attracted to. If you're only attracted to women, still uplift the voices of fat men (& other genders). If you like fatness up to a certain size, still recognize the personhood of a person over that threshold. If you are attracted to fatness but don't want your partner to be immobile or disabled, champion for the rights of disabled people (even if they're disabled from their weight, even if they gained weight as a choice). If you're smallfat yourself, make sure you're not discriminating against infinifats.
Body autonomy goes hand in hand with the trans community. If you're a feedist and you're transphobic, your interior views are not in alignment with each other. Someone's right to their body includes gender affirming care. Respect people's pronouns, even if you see a non binary person who is very femme presenting.
Treat feedist of color equitably. Not equally- equitably. People of color are at a disadvantage in society, and sometimes that means they need to be treated with extra consideration in some areas. Especially on Tumblr, I've seen many feedists of color express how terribly they've been treated by white feedists. What might be okay for a white feedist (dehumanizing, objectifying) could be horribly racist for someone else.
Don't involve people in kink without their consent. This doesn't mean "don't be visibly fat" in public. Because not all feedism content is explicit, this grey area is a little subjective. What might be uncomfortable for some isn't for others. Don't record people without their consent. Don't involve strangers in your scenes. (There's nothing wrong with fantasizing about someone without telling them, but once that comes into reality, it's crossing a line.)
Advocate for your fat friends. Make sure they feel included when you're out in public. Consider the spaces you visit and their comfort. Consider the amount of walking your plans include. Consider the heat.
Support content creators & sex workers when you can. Food is expensive, slow fashion plus sized clothes are expensive, healthcare is expensive, and a lot of them post a lot of content for free.
Listen to feedist's limits and respect them. Just because one person can eat four burgers and a dozen donuts doesn't mean everyone can.
Respect content creator's privacy. They might only be comfortable sharing limited information with you. If they've expressed that they don't want to show you their face/tell you their name, don't push. Many people could face challenges if those in their real life found out about their online identities. You don't have a right to anyone's private information beyond what they share with you.
Don't be dismissive of those with darker aspects of the kink. I don't care if you, personally, are only into soft feedism and death feedism gives you the biggest ick. Just because you're into into something doesn't make it wrong. Fetish communities are areas where those whose attractions are considered "deviant" or "obscene" bind together in solidarity to fight stigma and find belonging. Those with the most acceptable versions of the kink have to protect those with the most extreme. That doesn't mean you can't have "death feedists dni" in your bio (many do just so they don't accidentally engage in death feedism content as a trigger), but don't put them down.
If you're a feedist and you treat fat people as inferior; if you manipulate people into gaining weight without their consent; if you post/reblog pictures taken of strangers in public for your spank bank; if you comment gross and obscene comments on fat individuals who don't identify as feedists; if you view gaining weight as a moral failing (even if that arouses you); if you don't care for the rights of fat and disabled people; you're not a feedist! You're just a piece of shit :)
There is no feedism without ethical feedism. The rest of you are just fucking fat people and giving us a bad name.